The invention relates to a process for the closed-loop and open-loop control of an air-conditioning system and automatic air-conditioning system for motor vehicles and, more particularly to a process having a plurality of setting elements for one of a plurality of alternative working programs for the temperature control and/or air distribution. At least one setting element is provided for switching on an automatic mode, having in each case one temperature selection element for manually presetting a desired value of the temperatures to be set in the two side halves of the vehicle passenger compartment and having setting elements for air distribution in the two side halves of the vehicle passenger compartment.
A system of this kind is known from German Patent Document DE 3,427,292 A1. This system has a number of setting elements on its operating unit for primary functions--such as defrosting, cooling, air recirculation--which apply to both side halves of the vehicle passenger compartment and can thus be controlled with one channel. In addition, the operating unit has in each case one temperature selection element for secondary functions for manually presetting a desired value of the temperatures to be set in the two side halves. Setting elements, assigned in each case to the two side halves, are provided for separate working programs--such as automatic operation, maximum opening of the air flaps, closing the ventilation flaps--which can therefore be individually selected for the two side halves and thus controlled with two channels.
Due to the fact that also, at the least, the air distribution for the two side halves occurs separately, twice the number of setting elements are required on the operating unit and also twice the number of actuating elements are required on the air-conditioning box for actuating the flaps on the one hand. On the other hand, this results in a high outlay of material and a large degree of expenditure for actuation and control.
There is therefore needed a system of the generic type which can be optimized with respect to the cost/utility ratio.
This need is met according to the present invention by a process wherein when the automatic mode is switched on using the setting element, a single-channel temperature control occurs. The desired values manually preset using the temperature selection elements are overridden and the preset desired value for the one side half is made the same as the preset desired value for the other side half and used as a control variable. The automatic mode is switched off using the setting element. A two-channel temperature control occurs in accordance with the manually preset desired values at the temperature selection elements. The air distribution in the two side halves of the vehicle passenger compartment occurs with a single channel using the setting elements common to both side halves.
As a result, without noticeably compromising comfort with respect to the known system, a system is provided in which both a single-channel automatic air-conditioning system and a two-channel air-conditioning system with manual intervention are economically produced.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.